The black lead is a Outil of writing and drawing in the shape of pencil, generally without wood cases contrary to the Crayon undermines (sometimes also called lead pencil), which is composed of Plomb, of Argent or Alliage containing Plomb, of Bronze or tin. It is also called “style of lead” or “lead pencil”
|thumbnail|250px|center|Old black lead
History
The first use of the Plomb in the field of the writing was the layout of fine lines on the supports of writing to ensure the straightness of the written lines. Egyptians, Greeks and Romans use small discs of Plomb (in Latin: plumbum ) that they slip along a Règle “to regulate” the papyrus or the Parchemin. The pointed mines of Lead to regulate, put on page and to draw are attested in writings at the 12th century; the Theophilus monk writes that one “draws on the parchments with a Style formed of an alloy of three parts of Plomb for part of Bronze”.Different Ore S from Lead, cut out of rods, will be also used, their brittleness will make them cover with leather or to enchase in a wood sheath as of the 14th century, they are the ancestors of the Crayon undermines. In German one uses the word Bleistift for Lead pencil, literally meaning pencil of Plomb , which shows the origin of the crayon.
well During dredging of the the Seine to Paris under the Second Empire, of many black leads in more or less good state, dating from the the Middle Ages at the 18th century, were discovered. These pencils of Plomb were mainly manufactured and sold in the gravers located on the parapets of the Neuf bridge, from where them presence in the fleuve.
The mine of Graphite will compete with the mine of Plomb after the discovery of the layer of Graphite (called Plombagine) of Borrowdale in the Cumberland in 1564 then later of other layers in Germany.
However, the Graphite remaining very expensive until the 19th century, the mine of Plomb will remain a long time of use. At the 18th century the schoolboys still regulate their books with mines of Plomb.
Form - Manufacture - Use
Old black lead
The Lead or the molten Alliage was cast in a stone mould giving the form of the mine and the decoration of the head, then completed. The shape in half-moon of the head is in general decorated with religious or floral reasons and made it possible to regulate paper, just like the Roman discs.Modern black lead
The drawing tools sold today under the name of Black lead are not any more in Plomb or Alliage but in Graphite. The mine in Graphite is much larger than the mine of a Crayon undermines and makes approximately 5 to 7 mms in diameter. It is in general covered with a fine plastic film transparente.
They are used about like a Crayon undermines, but have the advantage of having a difference in contrast (reached by more or less strong pressure of the tool on the support) wider and generally a black more powerful than its equivalent out of pencil mine.
As for the Crayon undermines, one finds the dry ones and fats, the scale active of 9:00 (driest), with the 9B (fattiest), while passing by the HB and F.
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